Automatic telephone system



g- 1930. H. M.'FRIENDLY 1,772,713

AUTOMATIC TELEPHONE SYSTEM Filed Sepf.10, 1927 5 sheets-sheet 1 5: v EInvaniurg HerhEfl-FPFriEndly I wlyg- 12, 7 H M. FRIENDLY 1,772,713

AUTOMATI C TELEPHONE SYSTEM Filed Sept. 10, 1927 5 Shets-Sheet 2 JumpErsAug.12,1 930. H. M. FRIENDLY v v 1,772,713

' AUTOHATIC'TELEPHONE SYSTEM Filed Sept. 10, 1927 5 Street s-Sheet 5 549Lisa I 1,502

. scribers line or other line.

Patented Aug. 12, 1930 T UNITED STATES PATENT OFFICE nmaar 1r. ramnnnr,or cmoaao, rumors Auromrrc mason stem Application mue umber 1d, 1m.lea-1110. stapes.

The present invention relates to telephone systems; more particularlyso-called auto- 'matic ormachine switching telephone systems. I

General objects The general object of the resent invention is to enablea subscriber o the automatic telephone system, who contemplates leav ingthe location of his telephone, to directlve- 1y set central ofliceapparatus or call-forwarding enuipment associated with h s line througithe algency of his automatic calling device dia on his telephone, sothat m caseany calls are thereafter directed to 1115 line the lattersaid calls will be further extended or forwarded to a predetermined sub-The latter said line may terminate at the switchboardof an operatorwhois char ed with respond ng to such calls and imparting suchinformation to the party calling as instructed by the absent subscriberrimarily called. That 18, for ex ample, a p ysician, before leavin hisoflice' may remove the receiver of his te ephone as if to initiate acall, and then 0 rate 1118 calling devicedial by placing his ore-fin erin a s ecific depression fingerhold of the ialand tiien draw the dialuntil his finger encounters. the finger-stop, so that when the dial isreleased it willsend a series of eleven open impulses. After the dialhas returned, he will restore his receiver, leaving his central ofiicecall-forwarding equipment in the set condition.

As will appear presently, that due to the said set condition, any callextended to the terminals of the said subscribers line will not onlyring the bell of his telephone in the usual manner, but the call will bethereupon automatically extended or forwarded in accordance with thesaid set condition to an attendant who may possibly serve many suchsubscribers, or it may, as referred to, be ex tended to .a randomsubscribers telephone line as may be predetermined.

It -will also appear'presently, that if the subscriber has returned and,hears the bell he may respond in the usual manner and intercept the'callto the line to which in accordance with theset condition of his centraloflice call forwarding ap aratus the call would be otherwise finallyestined. This in terception also efiaces the said set condition so thathis line becomes in normal condition and remains so after thetermination of the call and until afain' directively set to forwardcalls as be ore. If the call is not intercepted b the subscriber asreferred to, the centra ofic'e a paratus s cific to thefprimaril calledsu scribers ine will cause the cal to be forwarded tothe prearrangedline. It will appear presently, that in case the call is forwarded to aswitchboard operator who may attend to callsfor a number of subscribersaccorded this class of service, the calls ex- .tended to her switchboardmay be extended thereto over a group of trunks common to all calls.

It will thus be perceived that the generalobject of the presentinvention is to 'pro' vide for savin calls in the temporary absence ofthe called subscriber. This not only relieves the subscriber of the dutyofremaining near his telephone to receive ossible calls, but it savesthe toll for the ot erwise futile call to'the operating concern. Thatis, ordinaril if no response is made to a call no-charge is collectedfor establishing the connection and the time the switching equipment isheld. Under the arangement contemplated in the present invention, if noreassesses a charge for a completed call from the calling subscriber tothe called subscribers line for which the calling subscriber pays as ifit were an ordinary, normally responded call, as well as also assessesatoll against the subscriber primarilycalled covering the forwarding ofthe call. 'That is to say, the calling subscriber will pay for the callto the line rimarily called'and the subscriber of the line primarilycalled will I y for .forwarding it to the point to which it isforwarded. The operating concern thus in place of being unable toreceive renumeration for a futile call, receives toll for two calls inyc'plllvedin the primary call and the forwarded Calls reguiringforwardin will usually occur at -business hours 0 the day when there isa sur lus ofv equipment, so that the forwarding 0 calls in which thedouble toll is collected logically comes at a time when there is ampleequi ment and correlated plant in idleness tohan le it. Of course, suchforwarding may occur during time of logically peak trafiic, but the1percentage of such latter calls will be relative y low becausetelephones will usually have attendance at such times.

While a meter M for registering the number of calls completed andforwarded has been indicated in ig. 1, in order to simplify thedisclosure, it will be understood that'any method of metering orprepayment collection may be employed under the contemplated use of theinvention. For example, the operation of the meters may be determined inpart by time of day the call is made, the destination of the call andthe duration of the call. That is methods of operating the metercontemplated in any well known or other methods, as for example, themethods shown in my Patents 1,694,169 granted Dec. 4, 1928; 1,694,170,granted 4 1928; and 1,726,983, granted Sept. 3, 1929. it alsocontemplates the' llection of pre-payment deposit as well known, andalso setforth in the latter said pliant. a

Drawings With reference to the accompanying drawin i-'.

' Fig. 1' shows a-subscribers tele hone A and companion line switch B;thesai line switch having common access to the switch group containinthe secondary line switch Fig. 2 s ows apparatus, nearly all of whichisspecifically employed in forwarding calls whli ch age primarilydestined to telephone A.

1g. s from the switch group containing secondary line switch C, togetherwith other indicated automatic switches and called telephones of wellknown systems. I Fi 4shows a well known so-called upselectlng connectorE, a group of suc connectors having access to a group of lines Iincluding the line extending to'telephone A in Fig. 1.

Fig. 5 shows the impulse .train transmitting apparatus cooperative withthe apparatus shown in Fig. 2.

- Fig. 6 shows a preferred modification of Fi 2. a

Fig. 7 shows a plan view of the dial of the lustrated in Figs. 6, and 11rotary ows a first selector F accessible present invention used on thecallingdevice (.40) on telephone A.

Fig. 8 shows a cross section along the line '8-8 in Fig. 7 disclosingthe detail of the Fig." 11 shows apreferred modification of 9 shows amodification of Fig. 2. 10 shows a preferred modification of Fig .h2. ge accompanying five sheets containing the dra illustrating the exemplaryembodiment o the present invention chosen to disclose it are assembledso that correspondingly designated lines extending toward marginsregister so-termed preferred modifications ilare to be considered asforming a part of 2. These modifications were not actually included inFig. 2 in order that the drawin would be less involved and thedisclosure t ereof more simple. That is, it has been deemed expedi- Theent to first disclose the main operation lndependent of certaindetailed, preferred operations in its comprehensive embodiment.

- The telephone A is' of the well known common battery automatic t butequ p ed with an automatic calling evice and dla of the presentinvention shown in Figs. 7 and i 8 so that a series of elevenimplulscscan be sent therefrom b 0 rating t e dial from a novel finger-ho d o theThe primary line switc B and the secondary line switchv C are of thewell known class as: described in the third edit on of Hershe sAutomatic Telephone Practice,

age 53. owever, thelower wiper, as well as the lower armature of theleft-hand relay shown on these switches, are specific to the presentinvention.

The first selector F is of the well known class-as des'cribedin the saidbook on pages .59 to 61. However, the lower set-of ofi-normal springs,the upper armature of the release relay, the upper armature of theswitching relay and associated circuits are specific to the presentinvention.

The switch elements NO and DF have the same general mechanical structure'and operation as the line switch B, though the operating circuits arespecific to the present invention. r

The dial of the calling device shown in Figs. 7 and 8 (and the callingdevice not shown) belong to the well known class as described in thesaid book of Hersheys on pages 15 to 17. However, the finger-hold ordepression used in setting the calling device to send eleven openimpulses is specific tothe present invention.

resent invention.

The line switches LS and LS are like line switch B.v a I The selectorsG, H, J, K, L,-N, P and Q are well known selectors as disclosed on pa cs59 to 61 in the said book of Hersheys.

e connector R is like connector E.

The tale hones AA, A and A are llke tele hone I 4 T e connector E is ofthe well known socalled group-selecting type I asdesignated Fig. 111 inHershe -s fourth'edition of his book Automatic Te ephgne Practice.

The selectors G, H, J indicated in Fig. 3 may described inthe thirdedition of said book of Hersheys, on pa cs 59 to 61.

The connector indicated in Fig. 3 is ofthe exact type of connector E inFig. 4, or it may be any other suitable connector, as for example, theconnector described in the third Initiating a call from telephone A totele- I phone A Upon removing the receiver from the switch-hook oftelephone A a circuit path can be traced from ground, armature .12,conductor 13, make-before-break spring 201, armature 202, conductor 203,telephone A, conductor 14, armature 205, make-before-break spring 206,conductor 207, resistor 16, armature 17, winding of slow-releasing relay19 to grounded battery, the latter said relay opcrating. In view of thestated well known operation of the switch B, its detailed operation inselecting and seizing the first accessible idle secondary line switch Cwill be understood. For thesame reason, the detailed operation of theswitch C in selecting the first accessible idle first'selector F will beunderstood. The first available idle selector F is thus seizedresponsive to the subscriber removing the receiver from the switch-hookof telephone A.

A large group of line switches containing switch B have common access'toa smaller grou of secondary line switches containing switc O. The groupof secondary line switches containing switch C then has common access toa smaller group. of first selectors containing switch F. The group offirst selectors containing selector F has common access to a group ofsecond selectors contam- I containin K L N P and Q be (if the cxactclass .mature 23 is a .plie

ing selector G. The up of second selectors I i I selector has'commonaccess to 1 Ya group 0 third selectors containing selector H and the upof third selectors containing se ector H as common access to a mu ofconnectors containing connector lhe cup of connectors containinconnector R as common access to the telep one line leading to telephoneA a When the telephone A has beenextended-to the first selector F, assetforth, switching relay 20 of switch B is actuated. Also, switchingrelay line relay 301 and slow-releasing release relay 302 of switch Fare actuated.

When relay 19 actuated forthwith responsive to the removal of thereceiver from the switch-hook of tele hone A, ground on ar- I d overrelease trunk conductor 24, con uctor 25, armature 208 to the winding ofrelay 209, the latter relay actuating to apply ground through itsarmature 210, conductor 211 to private bank contact 412 and itsmultiples to guard the line leading to telephone A against intrusion bya connector of the group'containing connector E.

Tom to indicate when call has been was to first selector When relay 302in selector F actuated, a circuit was thereby closed'from groundedofinormal spring 304, armature 305, conductor 306, bank terminal 26,wiper 27, armature 28,

I bank terminal 29, wiper 30, armature 31, conductor 32,make-before-break spring 213 to the winding of relay 214, the lattersaid relay actuating and locklng through its armature 215 to ground onconductor 25. At the time relay214 was energized ground on conductor 32also energized relay 216, the relays 214 and 216 thus actuatingslmultaneously. Specific tone from source ST is thereupon appliedthrough armature 217 upper armature of relay 216 to talking conductor14, audible to the party at telephone A, indicative that the connectionhas con extended to first selector F and that the first selector F is inreadiness to respond to the dial of telephone A.

It will be noted, in this connection, that the conductor 25 now receivesground back from attracted armature 308,. release trunk 309, bankterminal 33, wiper 34, armature 35, release trunk 36, bank terminal 37,wiper 38, armature 39 to the conductor 25, audit will appear presentlythat conductor 25 will be maintained grounded from ahead so long as thereceiver of telephone A is kept off the switch-hook so that relay 214will remain locked until the call is abandoned by the calling subscriberat telephone A.

.Callz'ng subscriber semis first digit of called I line number I Uponthe calling subscriber operating his calling dial 40 in accordance withthe first 21 of switch C is actuated. Also, Y

Ill

digit ll of the telephone number 83241 of the line extending totelephone A, the relay 801 will momentarily retract its armature 812three times responsive thereto, causing the wipers 313 to 315 to bealigned with the level of bank terminals and there rotate-in and selectthe first idle trunk leading to second selector G, the operation ofselector F being understood in view of .the reference to the thirdedition of Hersheys book, need not be detailed. However, it ma be statedthat after the second selector has been seized switching relay 316 isthe only relay in the selector operated, relays 301 and 302 deactuatingin sequence responsive to the actuation of the relay 316 in effectingthe seizure. The release trunk 309 will receive ground back fromselector G, in the well known manner before armature 308 retracts sothere is no lapse of ground potential on conductor 25.

Calling subscriber sends but four digits It is thought, inview of thereference to the third and fourth editions of Hersheys book, thesuccessive operation of the selectors G and H responsive to the secondand third digits and the operation of the connector R responsive to thelast two (fourth and fifth) digits to complete the connection from the'10 tele hone A to the called telephone A will be y understood. Y

At the time the wipers 313 and 315 were stepped ofi-normal and spring304 disconnected from its cooperative spring the ground traced to relay216 is thereby disconnected, so that relay 216 deactuates responsive tothe first impulse sent from the dial 40 and disconnects the tone sourceST. However, due to the locked condition of relay 214 ground appliedthrough armatures 218 and 219 1s conducted to the winding of relay 220,causing the latter said relay to-lock by its armsture221 to conductor25, thus positively disabling the application of tone from source ST solong as the present call is maintained.

Response at telephone .4

When the subscriber at telephone A' removes his receiver from theswitch-hook in responding to the ringing of his bell, current traversingthe heavy talking conductors, an including the telephone A, will bethereby reversed in direction. This will cause the differentiallyenergized magnet 'of the meter M to operatively energize cumulatively toregister a call against the telephone A.

It will be noted that the (lower) polal'lziwlifi winding of the magnetof the meter M be energized whenthe conductor 24 becomes current thentraversing the shunted (upper) operating winding ter said meter is thenin opposition to the polarizing winding. However, when 1 the calledsubscriber at telephone A is thefirst one of grounded when the call isfirst initiated. The wipers 42B of the magnet of the latg a busy tone tobe apphed audible m the reremoves his receiver from the switch-hook andcauses the direction of current traversing the shuntingresistor 16 andthe ofierating winding of the magnet of the meter to be changed indirection the two windings of the magnetof the latter said meterenergize cumulatively and cause the meter to register and the armature41 to short-circuit the resistor 16 and the operating winding. In viewof the adjustment of the magnet of the meter M, after the armaturesthereof operatively attract they will be maintained in their-attractedposition by the polarizing winding, regardless of the fact that thearmature 41 has short-circuited the resistor 16 and the operatingwinding to improve the talking transmission. Abandoning the call phone AWhen the subscriber at telephone A replaces his receiver on theswitch-hook the connector R will be restored andthis will incidentallyremove the ground from the release trunk forward extension of conductor25, so that all relays maintained locked from this ground dcactuate. Thecircuits are now at normal and idle. It will be noted in thisconnection, that had the calling subscriber at telephone A hung u hisreceiver first, while the called subscri r at telephone A maintained'hisreceiver 05 the switch-hook the connector B would not restore until thelatter'said subscriber hangs up his receiver, although the ground willbe momentarily removed from the release trunk back from the connector Rto unlock all relays dependent upon ground being maintained on the re-'lease trunk including conductor 25.

Y Call from telephone A to telephone A under 7 normal conditions In viewof the reference to the third an by subscriber at telefourth editions ofHersheys bo0k,. it is 4 thought that the extension 0 telephone A,through line switch LS, first selector J, second selector N, thirdselector Q and wipers 423 to 426 of connector E to the bank terminals427, 412, 428 and 429, respectively, (being telephone number 22312) willbe fully understood.

d Only first lineglfaqroup of three arranged for .fomarding n ccamplcdembodiment a call from the However, in this connection, it will be' explained that the line leading to telephone A agroup of three linesbelonging to the same subscriber all of which may be called by callingthe same telephone number 22312. If the first line is busy the to 426 ofthe connector E will pass on and seize the first idle line of theup'tested, and if none are idle will cause ceiver of the callin'telephone.

In view of the re erence to the fourth edithe private bank terminal ofthe first line of the grou cooperative with private wiper 424.

will-be tiedto its companion up private bank terminal cooperative witline of the group, ere bein no such tie for the last line of the, group.he said tie enables the connector to automatically step its wipers on tothe'next bank terminals horrespon'din to thenext positioned line of thegroup i the tested'line is busy. The absence of. this said tie disablesthe connector for automatically step ing its wipers on if the testedline is busy. he absence of the said tie also enables the connector to aply a busy tone audible in the calling telep one in the event aconnector'as will only app he busy tone if all the lines of the grou itis operated into selective relation wit are busy. Of course, one line maconstitute the roup and in that event if the line is busy "t e wiperswill not be stepped on and the busy tone will be thereupon applied,since the bank terminals cooperative with wipers as 423 and 424' are notto under the condition. Y

There is usually a group of connectors as E having common access togroups of lines be tied together and perhaps single lines as well. Theusual practice is to multiple the respective bank terminals correspon ngto 427 to a conductor as 431, and the terminals corresponding to 412 toa conductor as 432. These conductors from pairs ofcompanion bankterminals are connected to thecorresponding bank terminals ofeach'common connector and the airs of conductors correspondin to 431 an432 are left unconnected only i the corresponding-linepis the last lineof a group or 1s a single dine. That is, respective pairs of conductorsas 431 and 432 corresponding to companion" terminals simultaneouslyengaged by wipers as 423 and 424 are tied together for 1 all lines .of agroup excepting the last line thereof. This admits of assembling1 grou sand individual lines at random in t e ban g It will be noted that bankterminals 427 and 412, and respective multiples, correspondin to thefirst trunk of the group d esignated y the calling number 22312 are tiedtogether over conductors 431 and 432 through "spring 230 and that thecorresponding bank 424) for the next succeeding line 0 thegrou arepermanently tied to ether by he 433,.

terminals (cooperative with wi rs 423 while the corresponding ankterminals for the next (third as well as last) succeeding line of theoup are not tied. The arrangement is thus ecause only the first line ofthe group ofthree lines is arranged for forwarding. The last two linesof the oup lead directly from pairs of line terminals 434-435 and436-437, to telephones A! and AA, respecwiper 423; this being thearrangement for all-but the last sitions 22313 an 22314) wi (5 willappear presently. That is to say,

P to the first or second line 0 tively, but are only indicated .to avoidinvolvmg the disclosure unduly.

When first line of group is at z'ng the following lines of t a group arebarred when group number is called So it will be understood thatnormally the first idle line of the group of three belongi to thesubscriber having telephone A wi fi be seized and rung upon responsiveto setting the wipers 423 to 426 upon t a bank terminals correspondingto telehone number 22312; However, thelast two ines ofthe grou(occupying numerical o- 1 be disable so far as bein connected to bcalling the telephone num r,22312 at suc time as the subscriber may sethis first line of. the group leading to telephone A so that calls totelephone number 22312 will be forwarded as or forroardonl under t saidset condition all calls whereiii the wlpers 423 to 426 (or correspondingwipers of any eonnectorof the group containing connector E) are set uponbank terminals corresponding to the firstline of the roup 22312 willthen be forwarded to a pre etermmed line (in the present instancetelephone A) outside of the group, and if this first line of the groupis busy to give the busy tone to the calllng part One call can beforwarded and maintaine so at a time, in the arran ement shown in thedrawings illustrating t a present system, though, it will be fullydisclosed .presentl how this may, if desired be applied to all t elines-of the group. It has been illustrated in the limited manner toalvoid unduly involving the complete disc osure.

When first line of group is not set for for It. will be noted thatthefirst line of the said group is numbered 22312, while the followingtwo of the group are positioned as numbers 22313 and 22314,respectively. The second and third lines may be reached by directivelycalling the corresponding said telephone numbers or by directivelycalling the number of the first line of the group only under normalnon-set condition, wherein the connector will automatically advance tothe second or third line of the {group responsive the group being busy,as is well known, in view of-the reference to the fourth edition ofHersheys book.

ing the group of lines denoted by telep one number 22312, the operationof the system responsive to settin the wipers 423 to 426 upon the firstline 0 the group will be procceded with, having in mind the line leadingto telephone A is not set for forwarding calls.

contemplated by the present invention, as

With the foregoing explanations re ard- Line leading totelephone A busyIf it is assumed for the moment that the I line extending to telephone Ais busy by hav- (and its companion tied terminal 427 ing been seized byanother connector of the roup containing connector E or a' call has eninitiated from tele hone A, the private bank terminal 412 and t 1ecompanion group private terminal 427 tied through spring 230 willconstitute round potential. .The initiation of a call roin telephone Acauses the ground to be applied to ank terminal 412 y armature 210 in amanner peculiar to t e present invention as has been described. The wellknown operation of the connector E will cause the private terminal 412and companion terminal 423 to constitute ground potential if the line totelephone A 1s connected with by a connector of' the group containingcon nector E.

Under the condition, the wi ers of a connector set u on the line terminas corresponding to the ine leading to telephone A will step on to thenext successive set of bankterminals corresponding to the .second line(leading to telephone A) of the group, in the well known manner forconnectors of the stated type.

Line leading to telephone A idle When the connector E seizes the lineextending to telephone A (now assumed to be idle) itswiper-closing relay437 will cause ground otential to be applied through wiper 424, banterminal 412 (and multip es) conductor 432, conductor 211, armature'210to the winding of relay 236, the latter said relay actuating, itsarmature 237 applying ound through spring 238 to conductor 25, e ectiveto disconnecting the rela 19 and the ground normally applied throngarmature 12, in the well known manner and in view of the reference tothe third edition of Hersheys book.

The ringing current from source G is ap-' termittently a plied to t ebell 42 until the callin subscri r at telephone A. abandons the ca 1, orthe subscriber at tele hone A removes his receiver. from the switch-hookin position,

open impulses. It will be noted that'the deresponding. If the latter thetelephone A is ener through the back-bri ge 442 of t e connector E,after the ring-cut-o relay 438 operates.

It will be u ted that the 240and 241 short-circuit the rightand and lefthand windings of unlatchmg magnet 242, the

ob 'ect of which ma at will appear presently.

e calling telep one A an t ephone A are now in talking relation, theactuation of relay 442 havingreversed the direction of currenttraversing the telephone A. The talkin path from the wipers 425 and 426to telep one A is the same as that traced for the rin 'ng current tohell 42. The connector E wi restore responsive to the last said party tothe connection hanging his receiver on the switch-hook.

the line leading to telephone A so Setting calla directed'thereto willbe forwarded to I telephone A, the number of which is Let'it be assumedthat the subscriber of telephone A desires to have all calls directed tohis line oup No. 22312 forwarded to telephone num r 33241, which istributary to a different central oflice fromthat' to which the line totelephone A is tributary though the call may in like manner be sent to aline tributary to any oflice of the s stem.

Remembering that the 'al 40 on telephone A is like that shown in Figs. 7and 8, the subscriber at telephone A will remove the receiver from theswitch-hook to' initiate the call, causing the tele hone A to beextended to first selector F and the relays 209, 214 and 216 to actuatefor the objects before mentioned.

The subscriber will now appl his fin r to the depression Z of the dialas shown in i 7 and 8 and draw the dial around until finger encountersthe finger-stop and thereupon release the dial to restore to its normalthe while sending a series of eleven gflession Z takes the place of ahole for a gar-hold correspondin .to the digits from he called 1 to 0..This depression old is employed so as to not confuse the subscriber whensending by employing thenumeral holes in the 1a The selector F willoperate in the manner before referred to; but this time aligning itswipers with the eleventh level of bank terminals, in place of the thirdlevel. The relay 216 in Fig. 2 will deactuate res onsive to the firstofi-normal movement of t e wi ers 313 to 315 of selector F, and relay 2in Fig. 2 will thereupon actuate and lock to conductor 25 in the manneras before described. However, upon the wipers 313 to 315 with theeleventh levelof bank terminals, t e shaft 320 will cooperate with thesprings 321 and closethem, the wipers 1st ing bank terminals 323 to 325.The windings of slow-releasing relay 327 will now be 1 At the time theshaft 320 closes the springs in series with the tele hone A andattracted armature 328'will app y ground through bank terminal 323, wir313, armature 330 to release trunk con uctor 309 before armature 308has had time to retract, so that ground is maintained on conductor 24and exten sions, for the urposes above mentioned.

321, and before the wipers have had time to rotate in and seize theterminals 323 to 325 wherein relay 316 will actuate, a circuit can betraced from grounded armature 308, conductor 309,.armature 331, springs321, conductor 306, and over the traced path to conductor 32, tore-energize relay 216, causing the later said relay to actuate-to closea path from ground, armatures 218, 219, 241, spring 242,make-before-break spring 243, to the winding of slightly slow-releasinrelay 244, the latter said relay actuating an looking to groundedconductor 25. Ground on armature 245 is applied to energize relay 246causing it to o erate its s ring contacts and tripping the 0g 248 be 'ndthe armature proectron 249 on the relay-246. I Tone indicates when setbecomes efiectioe When the rela% 246 actuates, distinctive tone fromsource will be applied through spring 251, armature 252 to ta kingconductor 14, audible to the subscriber at telephone A, indicative tohim that the relay 246 has actuated to set the first line of his roupfor forwarding all calls directed to t e group when the first line isidle and for barring successive lines of his group against seizure bygroup-selection operation of the connector concerned. Ofcourse,-directively calling the second line of the grou will causetheselected lineto be seized 1f idle and the connector to rotate ofi' tothe third line of the group in the normal manner as if the statedsetting for forwarding calls had not been made. i

Means for b arring mceeaaive lines of group The barring of thesuccessive lines oft he group under the condition mentioned in theforegoing paragraph-is accomplished through the agency of the spring 230disengaging itscompanion contact and thereby openmg'the tie betweenconductors 431 and 432 so that busy gnoundpotential, cannot be appliedto bank terminal 427 andvits multiples.

It will be noted, in this connection, that at the time the relay 246actuated the shortcircuits were thereby removed from the windings of themagnet 242. This included them in series with the telephone A, so thatthe as dog 248 was thereby raised out of engageknowingl applied toprivate banlg ment'with the ative result. u I

The subscriber at telephone A upon'hearing the tone from'source T. andtherefore replace is receiver on the switch-hook. The wmdings of magnet242 will forthwith deenergize, allowing the dog 248 to retract and droover the projection 249. Theground wili bemaintained on the releasetrunk conductor 24 consistent with the slow-releasing characteristic ofthe release relay 329, so that an interval of time will occur after thedo 248 retracts before the relay 244 will unloc andthereby deenergizethe relay 246. When the latter occurs, its armature projection 249' ismechanically locked by the dog 248, so that the springs of relay 246 areheld 1n their actuated positions, although the winding'ofthe relay 246is unenergized. The lineleading to telephone A is now set so that anyprojection 249, but to .no oper that his line has been duly set, willcalls directed to it will be forwarded to telephone A, the numericalposition or telephone number of which is 33241. Subscriber at telephoneA may make-outgoing incoming calls I Let it be assumed that thesubscriber at telephone A desires to make an outgoing call during thetime the line is set for forwarding calls made to it. It-will be notedthat the relation between the line conductors lea'din between thetelephone A and the winding of relay 19 and ground on the restingcontact of armature 12 of the -rimary line switch B has not beendisturbe by the set condition of relay 246, so that outgoing calls fromtelecalls while the line is set to forward phone A will be normal underall conditions when the line is idle.

Call to line leading to telephone A while relay 246' is looked, andthelzne is therefore set 'to forward calls to telephone A the actuatedstate of relay 209 under the condition.

When the line leading to the telephone A (assumed idle) is seized by theconnector E, busy ground is applied, by the connector E to private bankterminal 412, and this ground is then applied over conductors432 and211,

armature 210 to operatively energize relay 236. Ground is thus appliedthrough armature 237, spring 238, armature 252 to the winding of relay253, the latter said relay actuating. This opens the talking pathbeterminal 412 due to I tween the telephone A and the primary linecopper tube) that it w v connector from the winding of slow-releasingline relay switch B. However, it will be noted that the ringing path tothe bell 42 is the same as before described, with the sole exceptionthat the windings of the magnet 242 are in series therewith. The core ofthe latter said magnet is so designed (as b shielding it by a ill not beoperatively susceptible to the alternating ringing current, from sourceG, when in series with a condenser at the bell 42, but will operate itan energized conductive path is closed through a source of directcurrent, as b the removal of the receiver from the switchoo k oftelephone A. The bell 42 will thus start ringing res onsive to the saidseizure by the scriber of tele hone A hears the bell he may respond andt ereby un-set his line'and proceed as if his line had not been set,when the call was extended to his line. This operation will be taken upin detail later on.

Forwarding operations Returning to the. actuation of relay 253responsive to the connector E seizing the line leading to tele hone' A,a circuit can be traced 19 in the primary line switch B, armature 17,conductor 207, make-before-break spring 206, armature 255, conductor256, armatures 501 and 502 in multiple, conductor 503, armature 257,make-before-break spring 201, conductor 13,- armature 12 to ground, therelay 19 actuatin It will be noted that the loop including t e armatures17 and 12 of the primary line switch B is equivalent to the conditionwhen a call was describedinitiated from telephoneA, so that it 'will beclear that the primary line switch B will 0 erate to extend theconnection from multiplied armatures 501 and 502 to a secondary lineswitch as C, andthat the latter will then further sponding to the numberof telephone A.

extend the connection to a first selector as F.

When 'the first selector F is seized and ground from spring 304 isapplied back over the before traced path tothe windings of relays 214and 216, the latter two relays actuating the relay 214 looking torelease trunk ground, as before described. Ground will now be appliedfrom armature 258, through armatures 259 and 260, conductor 261 to thewinding of relay 504, the latter 'said relay actuating to start thepredetermined directive impulse series -train corre- Inasmuch as in theassumed case the call is to be forwarded to telephone number 33241(telephone A), the terminals on the crossconnecting rack set Xcorresponding to the numerical orders of the five digits of thetelephone number of the telephone line leading to telephone A will bejumpered to digit terminals Y on the cross-connecting rackhaving thedesignated digit value corresothat in the event the sub-- mums spendingwith the-numerical order rank of t e di ber, t e cross-connecting rackterminals Y being designated in accordance with their digit value tocorrespond to the bank sitions of corresponding, digit value 0 theswitch DF.

It will be clear, presently, that if it were 539- 536, u" per armatureof relay 504 to the winding 0 relay 515, the latter said relay actuatingand locking to the attracted armatelephone A is therefore un-busied andtherefore subject to seizure while the shafts 552 and 533 of switches NOand DF', r tively, are oif-normal the relay 515 wil be prevented frombeing energized responsive to a new seizure of t e line leading totelephone A until the wipers 513 536 and539 are in their drawn ositions.the line correspon ing to telephone A may beseized, causing the relay504 to rea-ctuate, before the switches NO and DF have had time torestore, but the relay 515 cannot initiate the sending of impulses untilthe latter said switches have first restored to nor mal. This operationwill be described in more detail presentl The interrupter F matelytwelve revolutions per secon being the rate it is desired to senddirective imulses to the switches forwarding the call. e first impulsedelivered over conductor 516 through armature 517 after'the actua-.terrupter I until relay 523 actuates, as will a pear presently.However, it will be noted t the traced path including conductorsrevolves at a proxits of the letter said telephone num- 'ture 514. Thiscloses theconductor 516 lead- 'lhat is to say, 1

Ill

III

256 and 503 will not be opened by the attraction of the armature 501 solon as armature 502 remains retracted. hen wiper 524 is stepped to bankterminal 527 responsive to the interrupter 1 ground isapplied fromground 528 over conductor 529 throu h armature 530 to the winding ofrelay 531, the latter said relay actuating.

Sending of forwarding impulses wiper 536 engages bank terminal 535 acircuit path can be traced from grounded armature 511, wiper 513, jumper538, digit terminal3 of the cross-connecting rack group Y, bank terminal535 wiper 536, wiper 539, bank terminal 540, conductor 541 to thewinding of slow-releasing relay 523, the latter said relay actuating,armature 530 locking it through wiper 524 to ground 528 so long as wiper524 is off the bank terminal it is shown resting upon. When the relay523 actuates, armatures 501 and 502 will retract to maintain the closureof the circuit path including the conductors 256 and 503 in order togive the selector F time to. rotate in and seize the first idle trunkextending in the direction of the telephone A; leading to secondselector G, Armature 545 applies ground received from conductor 529overconductor 546 and through the interrupter contact and armature 547to operate the motor magnet 520 to restore the wipers on shaft 533 tothe drawn position at which position the ground 528 is free of conductor529.

Armature 549 applies ground to the winding of motor magnet 550, so whenrelay 523 deactuates the Wipers on shaft 552 will be advanced one step.vWiper 513 now applies ground over jumper 553 to bank terminal 535,corresponding to digit Also, due to the deactuation of relay 523, theinterrupter I will start driving the wipers on shaft 533 in the mannerasbefore described until. the wiper 536 encounters bank terminal 535,causing three open-impulses to be transmitted from armature 501effective to selector G, the Wipers on shaft 533 restoring to the drawnposition thereafter as before described when the first series of threeopen in'ipulses were sent. The shaft 552 will be caused to advance its.wipers when the relay 523 deactuates following the sending of the seconddigit 3. Wiper 513, now applies ground over jumper 556 to bankterminal557 correspond,- ing to digit 2. i

lhe wipers on shaft 533 will now be driven until wiper 536 encountersbank terminal 557, at which time the relay 523 will actuate and lock andthe wipers on shaft will be restored to the drawn position in the manneras before described, the armature 501 having sent a series of two openimpulses effective to third selector H. In view of the jumpers 561 and562 two more series of open impulses will be sent; the one correspondingto j umper 561 being a series of four, and the one correspondingtojumper 562 being a single impulse. The last two series serve to setthe connector R on the terminals of the line (assumed. idle) leading totelephone A, the connector R thereupon applying ringing curre nt tooperate the signal bell'of telephone Bell of telephone A is rung whilecall is being forwarded and until subscriber at telephone A respondsDuring the sendin of the train of series of open impulses to efiect theforwarding extension to the line leading to telephone A the bell 42, oftelephone A has been periodically ringing responsive to sourceG, appliedfrom the connector E, so that the subscriber thereof (telephone A) if athand may respond and thereby efface the extension of the call towards orto the telephone A and thereby destroy the set-up condition by operatingthe magnet 242, as will appear presently.

Let it be assumed that the subscriber of telephone A does not respond tothe call during the time the forwarding extension train of series wasbeing sent or before the response at telephone A. ,7

At thetime the motor magnet 55 0 retracts the fifth time following thetermination of the fifth digit series and before the shaft 533 has hadtime to stepits wipers in two steps, ground is applied from bankterminal 563 where ground potential has existed since te relay 515 firstactuated ,and so constantly maintained), wiper 564, conductor 565,makebefore-break spring 263 to the winding of relay 264, the latter saidrelay actuating-and locking through armature 252, spring 238, armature237 to ground, it being remembered that the ground is maintained on thearmature 237 of relay 236 by the connector E energizing the latter saidrelay.

Subscriber (22 telephone A can answer calling party untilealling partyhangs up Responsive to the actuation of relay 264, a

at any time until the call is abandoned by the calling subscriber andthereby come in on the connection and efl'ace tho forwarded extensionand become in direct talking communication with the calling party, as ifthe line extending to telephone A had not been set to forwarded'callsdirected thereto.

\Vhen the relay 264 actuated and relay 253 deactuated, the windings ofthe polarized relay 265 is placed in bridge of conductors 13 and 207extended to connector R. While the bell of telephone A is being rung,the armature of the polarized relay 265 is tilted counter-clock-wise sothat the slow-releasing relay 266 will be operatively energized.

Response at telephone A comes current to be reversed through callingtelephone A \Vhen the receiver is removed from the switch-hook oftelephone A the currentprojected back from the front-bridge rela ofconnector R responsive to the actuation oi the back-bridge relay ofconnector R :will hereversed in direction through the winding ofv thepolarized relay 265, under which condition its armature will tiltclock-wise so that relay 267 will be operatively energized, the relay266 deactuating consistent with its slow-releasing characteristic.

The armature 270 will now close a conductive path including theretardation coil 271 in series for operating the ring-cut-ofi relay 438in connector E, followed by the actuation of the back-bridge relay 442.So the current will not only be reversed back to the polarized relay 265responsive to the subscriber at telephone A removingthe receiver fromthe switch-hook, but the current will be reversed back over the lineincluding calling telephone A by the operation of relay 442, consequentthereto.

Tone to indicated call is a forwarded one It will be noted that afterrelay 267 actuates, and before relay 266 has had time to deactuate, thedistinctive tone from source AT is a plied through armatures 272, 273audible to t e party at telephone A and the party at telephoneindicative to them that the call was a forwarded one.

Recording number of calls forwarded least there will be a record made onthe meter of a completed call.

Meter of line primarily called registers forwarde calls It will be notedthat the reversal of the current back from'the connector B when theparty at telephone A responds will affect the meter M associated withthe primary line switch B as when a call was described as initiated attelephone A and responded to at telephone A, so a call is registeredagainst the subscriber of telephone A covering the forwarding of thecall. The meters M and M thus enable detailed information to be had asto the number of calls assessed to the subscriber of telephone A and thenumber of these which represent forwarded calls.

Indication by tone given calling party while zcall is being forwardedfrom the called "from spring of relay 246 to the right han terminal ofthe winding of retardation coil 271 to effectuate the stated object.

Talking path between calling telephone A and called telephone A When therelay 267 actuated, the talking path from telephone A to conductors f439-440 is continued through condensers 281-282, armatures 205-202,springs 206-201, conductors 207-13, armatures 17-12 respectively," andover the heavy talking conductors to the telephone A.. From conductors430-440 a line pair leads through windings of magnet"'242, lineconductors 14-203, respectively, to telephone A, the impedance of thewindings of magnet 242 being sufiicient to prevent undue attenuation ofthe currents constituting sound which pass between the telephone A and Abecause of the electro-static capacity of the line conductors leading totelephone A.

Subsci'ibei at telephone A replaces receiver on-switch-hoolc whilesubscriber at telephone A retains his receiver of 1 from the bridge, sothat the back-bridge relay 442 in connector E will deactu ate. Thewinding of polarized relay 265 is still in series with the front-bridgerelay in connector R, so that the latter said connector is still inseizure of the line leading to telephone A.

Subscriber at telephone A 'replaces receiver on switch-hook Upon'thesubscriber at telephone A now replacing his receiver on the switch-hookthe front-budge relay 446 in connector E will deactuate and cause theobvious circuit for the release ma net of connector E to energize torestore said connector E. This will remove the ground from conductor211, so that armature 237 will retract and deener ize relay 264, thusremoving the winding 0 olarized relay 265 from the said series re ationwith the front-bridge relay inconnector B, so that the said connector Rand antecedent switches employed in forwarding the call will thereuponbe restored, the circuits employed in the call being new normal'and inreadiness for a new use.

Subscriber at telephone-11 replaces receiver on switch-hook whilesubscriber at telephone A retains his receiver of 1 If the subscriberattelephone A first replaces hisreceiver after terminating theconversation, the deactuating of the fronta bridge relayv 446 inconnector E resultant thereto, will cause a circuit to be prepared forthe release magnet of said connector E and the ound removed from therelease trunk so t e antecedent. switches Q, N, J and LS will restore,the said connector E remaining in seizure, since the retardation coil271 is still in series with the back-bridge relay 442. The winding ofthe polarized relay 265 is still in series with the front-bridge relayof connector B, so that the replacing of the receiver at telephone Aproduces no operative efi'ect beyond connector E.

back-bridge relay of connector R will deactuate to restore the directionof current traversing the winding of polarized relay 265 so that therelay 267 will be deenergized and thereby removethe retardation coi 271from the bridge,

winding of the polarized relay 265 is still in so that the back-bridgerelay '442 in connector E will deactuate. The

series with the front-bridge relay in connector B, so the latter saidconnector is still in seizure of the line leading to telephone A.

When the back-bridge relay 442 in connector E deactuates it closes theobvious circuit for the release magnet of connector E to operate torestore said connector E. This will remove the ground from conductor211,

1 so that armature 237 will retract and deenergize relay 264, thusremoving the winding of the polarized relay 265 from the said seriesrelation with the front-bridge relay in connector R, so that the saidconnector R and antecedent switches emplo ed in forwarding willthereupon be restored: the circuits employed in t e connection being nownormal.

Restoration of impulse sending apparatus circuit for relay thewipers'thereon to the position drawn.

Ground from armature 567 will be applied through wiper 572 and throughthe interrupter armature 547, causing the shaft 533 go restore thewipers thereon to the position rawn.

Calling party abandons the call while forwarding impulse train'is beingsent grounded there is no ground on bank ter-* minal 412 and multiplesthereof to bar the line leading to tele hone A against seizure, so thatthe line lea therefore become immediately seized by a. connector of thegroup containin connector E before one or both of the shalts 552 and 583of elements NO and DF restore to'the drawn position. This is having inmind that at the time conductor 211 is ungrounded, the conductor 25 maystill constitute ground due to the slow-releasing release relayconcerned not yet having deactuated. This will cause relay 209 tomomentarily actuate the cause armature 210 to apply ground to conductor211. However, the conductor 211 may being to telephone A may armature511 may come-finally ungrounded before the elements NO and DF have hadtime to restore. I

In order to revent the relay 515 from being reactuate responsive to anew seizure of the line leading to telephone A until the latter saidelements have restored to normal position which said actuation wouldvitiate the call starting the impulse train prematurely, w ierein theproper train may not be sent,.the circuit energizing relay 515 cannot beclosed until the wi ers of the latter said elements have restore so thatground from be applied through wiper 513 and its normally enga ed banktermina and the normally engaged ank terminals cooperative with wipers536 and 539.

Line leading to telephone A encountered busy when call is forwardedthereto If the line leading to telephone A is encountered busy when thecall primarily directed to telephone A is forwarded thereto, the busytone applied to the talking conductor in connector R will pass over thelower talking conductor'to conductor 13, spring 201, armature 202,condenser 282, armature 270, tone condenser, armature 273, conductor439, wiper 425, ringing tone condenser 445, audible to the subscriber attelephone A, having in mind that this tone will be particularlydistinguishable during the silent ringing 'periodswith respect togenerator G, since there will be a ringing generator (G) tone audibleduring the live ringing periods.

Unsetting 0 the line leading to telephone A so calls irected theretowill not be forworded The set condition referred to will endure untilacall is responded to by the'subsc'riber at telephone A wherein aconductive path is included in series with the windings of magnet 242,energized from the ring-cut-ofl' relay 438 and back-bridge relay 442 ofa connector as E. That is, a subscriber may return to his telephone andif on call comes to it he will answer forwarding apparatus, but if no.call comesiu he can leave again with the forwarding apparatus still inits set condition, notwithstanding that he may have made outgoing callsfrom his telephone.

Forwarding calls to an attendants position provided (for answering callsforwarded when ran om lines are called In the foregoing descriptions thecalls to a specific telephone ne leading to telephone A wereforwarded'to telephone A. It will be clear that random lines may havethe'same cross connections in the respective impulse transmittingdevices so that calls may be forwarded from any number of lines to thetelephone A. Moreover, a roup of lines num- 05 her 33241 leading fromthe group of connecplace of extending to the l 563 will be moved to itand there y unset the 7 ing the conversation between t tors containinconnector B may be used so 1 plurality of ca ls may be received by thesubscriber At on a corresponding plurality of telephones or on anattendant s switchboard, for examp e. Again, a group of trunks leadingfrom selector H ma extend to an attendants switchboard. this lattergroup is assumed to be in the second bank level, in oup of connectorscontaining connector R, t e cross-connecting iumpers 561 and 562correspondin to the set two digits will be omitted, and in that eventthe conductor leading to bank terminal bank terminal 574. Of course, thejumpers on the cross-connecting rack may be changed from time to time asdesired, so that calls directed to the corresponding telephone line willbe forwarded to any desired telephone number.

Pause between series of the impulse train Due to the slow-releasingcharacteristic of therelay 523, after it actuates to terminate a digitseries, a predetermined time will ensue before it deactuates to enablethe next series.

Modification of circuits to disable the line em tension to telephone Aas soon as the last imgalse of the forwarded train has been sen Fig. 9shows a modification of the circuits.

in Fig. 2, introduced as indicated by the dotted section lines a, b and0, so that when relay 264 actuates when the forwarding impulse tram hasterminated, the extension to telephone A is cut oil by relay 264 and thebell at telephone A will cease to ring. This arrangement thus preventsthe forwarded extension (to telephone A) from being intruded upon by thesubscriber at telephone A after the forward extension is completed, andit also cuts off the leg to tele hone A dur- As d A, e. telephonePreferred modification which disables subscriber at tele hone A fromintruding only after subscri er on line finally called is sponds Anothermodification of the circuits of Fig.

2 and which is the preferred one, is shown in Fhg, 10, introduced asindicated by the dotted sect on lines a and d, so that when the relay267 actuates upon theresponse at the telepiionet Akthe leg leading totelephone A will cu o Modification of circuits to denote b distincthetone audible in telephone when aoall is initiated whether "line is or isnot set for forwarding Y Fig. 11 shows a preferred modification of thecircuits in Fig. 2 involving the addition of an extra spring 290 andmake and break cooperating contacts on the relay 246. A specific tonesource FT is added. It will be clear that when the relay 246' is locked,and

I; the line leading to telephone A is thereby set so that calls directedthereto will be forward ed to telephone A, the tone source F'I will besubstituf ed for'tone source ST to armature 217 on relay 220.' Thus, ifthe subscriber removes his receiver as the switch-hook after setting hisline for forwarding he will per-.

ceive thespecific tone from source FT indicative that the setting ismade. The tone re-.

ceived will also prompt him-of the condition when initiating an actualcall.

'Meansjor uneetting the apparatus so calls will not be thereafterforwarded have the said set condition of his line effaced, so that callswill not be responded to if he does not choose to do so from histelephone A, be may call his own telephone numor from some othertelephone ofhis group, perhaps, but not from telephone A (because toinitiate a call from telephone A will bar his corresponding line againstseizure), and when the bell of telephoneA starts ringing remove thereceiver thereof from the switchhook and thereby unlock the relay 246,in the manner before described wherein the windings of the magnet 242energized in series with telephone A on incoming calls when the relay246 is locked. Of course, the subscriber at telephone A mayalternatively call some subscriber, perhaps the subscriber of telephoneA and reporthis 'return'and request that his line (leading to telephoneA) be called so that he may respond to the call and thereby unlock therelay 246..

With reference to the last foregoing paragraph, it will in most casesnot be desired to directively unset the forwarding apparatus as any callmade to the line leading to telephone A will be responded to on thelatter B5 The modification of Fig. 2 shown in Fig.

said line before it has been forwarded to telephone A and this willunlock relay 246. In case the subscriber of telephone A again leaveswherein no call has been responded to by him since setting the relay 246the set-up condition still endures. There is no means for a party at atelephone other than at telephone A to unlock the relay 246, unless itbe the central ofiice attendant manually unlocking relay 246 by trippingdog 248.

. Modification of unlatohing magnet 6 changes the winding on magnet 242in Fig. 2 to a simple winding and the shielded core to a simple core.The windin taken from the magnet 242 are placed on to core of the relay601'. The core of the latter said relay is shielded by a copper tube tomake it unresponsive to alternatin or ringing current from the source G.T e ma at 242 is then energized in a local circuit 0 the relay 60. Themagnet 242 requires considerable energy to operate its dog to unlatchthe relay 246, so that a relatively few terms of windings on the relay601 will sufiice, as compared to the num ber-of turns required where thetwo wind- UommeroiaZ embodiment It will be noted, that in the commercialembodiment of the present invention, sets or units of'equipment as shownin Figs. 2 and 5 ,(in view of the preferred embodments mentioned) willbe rovided in sufiicient number at the central 0 cc. Then any subscriberre questing to be supplied this special service will have such a unitcross-connected into his line as indicated by the jumpers joining therespective terminals a'-a", b'b, cc", n,- l n, flzll gl gll,'hl -hlln'-n". That is, i no special unit as contemplated by the presentinvention is to be emp oyed, the jumpers shown joining the last saidsets of terminals will be removed and jumpers or tie conductors insertedbetween The subscriberobtainin the service contemplated by the presentinvention wherein callswill be forwarded to a predetermined line oftheexchange when desired, will perhaps pay a monthly rental or otherconsider-- ation for the special service provided for him, and thischarge may also com rehend the number of calls forwarded as indicated bythemeters M and M.

While only the first line of the group of three is shown arranged forforwarding, it will be clear that all the lines may be so arranged bythe use of like circuits, having in mind that if the second line of thegroup is thus equipped the circuit through the spring 230 will bepermanently closed. And, if the third line of the group is thus arrangedthe circuit corresponding to the last referred to for the second line ofthe group will'also be permanently closed. The circuit for the thirdtrunk corresponding to the last re'-' ferred to will be leftpermanentlyopen under the condition of being arranged for forwardingcalls directed to it.

Where the term relay is employed in the subjoined claims, this term isto be understood as referring to any electro-magnetical- 1 operatedcircuit-switching device, such fbr example, a wiper step-by-step switch.

Having set forth an exemplary embodiment of the present invention, itwill beunderstood that the invention is ca able'of modification and sial use within t e scope of the subjoined c aims.

I claim I 1. In a telephone system, a calling line, a first called line,switch apparatus for extendin a call from said calhng line to said firstca ed line, a second called line, automatic switch mechanism, a manualswitch on said first called line, and means the operation of which ispredetermined by an operation of said manual switch for predeterminingwhether said automatic switch mechanism will 0 rate to forward theconnection from the ca ling line to said second called line responsiveto efiectin connection from said calling line to said rst called linewherein rtion of said first called line forms a a fifii of theconnection to said second called 2. a telephone system, a movable switchterminal, a first called line, a fixed terminal of said line cooperativewith the movable terminal, a second called line, a relay, automaticswitch mechanism, a manual switch on said first called line, meanscontrolled over a talking conductor of said first called line foroperating said relay and for retaining it operated res onsive to theoperation of the manual switch, means for setting said movable terminalon the fixed terminal to thereby efiect connection from the movableterminal to said first called line, and means dependent upon said relaybeing operated when the movable terminal is set upon the I fixedterminal for causing said automatic switch mechanism to operate to linka connection forward from said fixed terminal to said second'called linewherein a portion of sa dfirst called line forms alink of the connectionto said second called line.

3. In a tale hone system, a movable switch terminal, a ed terminalcooperative with said movable terminal, a directive device, switchmechanism, a called line, a relay, means for energizing said rela over.a talking conductor of the called line to set the relay, and meansoperated responsive to setting said movable terminal on said fixedterminal only if said relayhas been previously set for causing thedirective device to operate the switch mechanism to link a connectionfrom the fixed terminal to the called line.

4. In a telephone system, a calling line, a first called line, a firstautomatic switch mechanism for linking a connection from the callingline to said first called line, a relay, means controlled over a talkingconductor of the called line for energizing the relay to set the relay,a second called line, a second automatic switch mechanism for linking aconnection from the said first called line to said second called line,and means the operation of which is determined by the set condition ofsaid relay only if the aet'condition is existent at the time said firstcalled line is connected to it for forwarding said connection byoperating said secon automatic switch mechanism to com lets theconnection to said second called us wherein both said mechanisms arelinks of the connection to the said second called line.

5. In a telephone system, a calling line, a first called line, a firstautomatic switch mechanism for linking a connection from the callingline to said first called line, a relay, means controlled over atalkinglconductor of the called line for energizing t e relay to set therelay, a second called line, a second automatic switch mechanism forlinking a connection from the said first called line to said secondcalled line, means the operation of which is determined by the setcondition of said relay only if the set condition is existant at thetime said first called line is connected to it for forwarding saidconnection by operating said second automatic switch mechanism to comlets the connection to said second called hne wherein both saidmechanisms are links of the connection to the said second called line,and means controlled over said first called line forunsetting the relay6. In a telephonesystem, a calling line, a first called line, a firstautomatic switch mechanism for linking a connection from the callingline to said first called line, a relay, means controlled over a talkingconductor of the called line for energizing the relay to set therelayila second called line, a secon automatic switc mechanism forlinking a connection from the said first called line to said secondcalled line means the operation of which is determined by the setcondition of said relay only if the set condition is existant at thetime said first called line is connected to it 'for forwarding saidconnection by operating said second automatic switch mechanism tocomplete the connection to said second called line wherein both saidmechanisms are links of the connection to the said second called line,and means controlled over said first called line for unsetting the relayand for thereu on efiacing the forwarded extension to sai second calledline.

7. In a telephone system,1a calling line, a first called line, anotherline, first switch mechanismfor linkin a connection from said callingline to said rst called line, second switch mechanism for linking aconnection from said first called line to said another line, a signaldevice on each said lines, a settin means including said first switchrelay, mec anism for extending a call torsaid first called line and forthereupon causing the corresponding said signal device to operate, meanscontrolled over a talkin conductor of said first called line foroperatmg saidsetting relay before said connection is estab-' lished, andmeans operated responsive to extending connection to said first calledline onl if said relay was beforehand set to cause sai second switchmechanism to forward the connection from said first called line to thesaid another line and cause the corres onding said signal device tooperate whi e not disabling the operation of said signal device on saidfirst called line.

8. In a telephone system, a calling line, a first called line, anotherline, first switch mechanism for linking a connection from said callingline to said first called line, second switch mechanism for linking aconnection from said first called line to said another line, a signaldevice on each said lines, a setting rela means including said firstswitch mec anismfor extending a call to said first called line and forthereupon causing the corresponding said signal device to operate, meanscontrolled over a talking conductor of said first called line foroperating saidosetting relay before said connection is established,means operated responsive to extending connection to said first calledline only if said relay was beforehand set to cause said second switchmechanism to forward the con nection from said first called line to thesaid another line and cause the correspondin said signal device tooperate while not disa Im the operation of said signal device on saxfirst called line, and means controlledover said another line fordisabling the operation of the signal device on the said first calledline while maintaining connection from the calling line to the saidanother line wherein 'a portion of said first called line .is a link ofthe connection.

9. In a telephone system, a calling lme,.a first called line, anotherline, first switch mechanism for linking connection from said callingline to said first called line, second switch mechanism for linkin aconnection from said first called line to saidanother line, a signaldevice on each said lines, a setting relay, means including said firstswitch mechanism for extending a call to said first called line and forthereupon causing the corresponding said signal device to operate, meanscontrolled over a talking conductor of said first called line foroperating said setting relay before said connection is established,means operated. responsive to extendin connect-ion to said first calledline onl if said relay was beforehand set to cause said second switchmechanism to forward the connection from said first called line to thesaid another line and cause the corresponding said Sig-- nal device tooperate while not disabling the operation of said signal device on saidfirst.

called line, means controlled over said another line for disabling theoperation of'the signal. device on the said first called line whilemaintaining connection. from the calling line said first called line.

of said first'called line is a link of the connection," and meanscontrolled over the said first called line for disabling theoperation ofthe signal device on said another lme while maintaming connection fromthe calling line to 10. In a telephone system, a calling line, a

first called line, another line -firstswitch mechanism for linkingconnection from said calling line to said first called line, secondswitch mechanism for linking a connection from said first called line tosaid another line,

a signal device on eachsaid lines, a setting' relay, means includingsaid first switch mechanism for extendinga call to said first calledline and for thereupon causing, the corresponding said signaldevi'ce tooperate,,means controlled over a talking conductor of said first calledline for operating said setting relay before said connection isestablished, means operated responsive to extending connection to saidfirst called line only if said relay was beforehand set to cause saidsecond switch mechanism to forward the connection from said first calledline to the'said another line and'cause the corresponding said signal Idevice to operate while not disabling the operation of said signaldevice on said first called lme, means controlled over said another linefor disabling the operation of the signal device on the said firstcalled line while maintaining connection from the calling line a -to thesaid another line wherein a portion of said first called line is a link'of the connection, and means controlled over the said first called linefor elfacing the forwarded extension to said. another line whilemaintaining connection from the calling line to the saidfirst calledline.

11. In a telephone system, a calling line, a first called line, anotherline, first switch mechanism for linking a connection from said callingline to said first called line, second switch mechanism for linking aconnection' from said first called line to said another line', meanscontrolled over said first called line only before said first switchmech-- anism links connection to said first called line for preparing acondition for causing.

said second switch mechanism to link a connection from the said firstcalled line to said another called line responsive only to saidponnection being linked to said first called me. I

12. In a telephone system, a calling him, a first called line, anotherline, first switch mechanism for linking a connection from said callingline to said first called line, second switch mechanism for linking aconnection from said first called line, to said another line,

means controlled over said first called line only before said firstswitch mechanism links connection to said first called line forpreparing a condition for causing said sec-

